T5 vs LED, which is better?

July 23, 2020 3 min read

T5 vs LED, which is better?


The term 'T5' refers to the diameter of the fluorescent tubes which are 5/8 inches in diameter. T5s produce more light than T8/T12 tubes which are older in design.

T5 bulb definition

T5 light being older technology, it is more stable and gives very predictable results. It has years of proven usage by expert aquarists as well as the horticulture industry.

There is a wide variety of bulbs across a spectrum of colours available on the market, so making adjustments to your light spectrum profile is easy. Efficacy is dependent on bulb quality and fixtures that have better built ballasts last longer. Reflector design can make a large difference in the actual amount of light shining into the tank. Hydroponic light fixtures that fit the tank size gives the most bang for the buck. Shop-lights fixtures can give good value as well.


The main advantage of LED over T5 lights is that it is more efficient, which will save cost (bulbs & power) in the long run. Designs are often more sleek. 

Picking a commercial LED light for a planted aquarium that works well can be tricky. The technology is new and there are huge differences in quality & output between brands. Most cheaper fixtures on the market do not have an attractive spectrum selection and many are rather weak for growing plants. LEDs also do not produce UV light by default (unless UV diodes are used), while florescent lighting does.

It takes real depth of knowledge to know what to look out for in an LED fixture. Despite claims of "full-spectrum" or "plant specific" lighting - many fixtures on the market are still generic and while many do an okay job growing green plants, they are poor at stimulating pigmentation in red plants, especially when compared to higher end T5 specialty bulbs.

LED Recommendation:
Many commercial fixtures will work okay, but finding a truly great one is difficult. We think that understanding PAR values and spectrum selection are the basics that one should know before making an LED purchase. ​There are a selection of LEDs that work better than the rest because of their focus on having more RGB rather than white LEDs, giving better color pigmentation and visual saturation than their peers, you can read about it in this article.


There is no physics difference in light being produced by an LED or T5 unit; however reflectors in different units can affect whether light beams are more collimated (better penetration in deep tanks) and of course, different units produces light of different spectrum/wavelengths. It is still generally easier to tune to get a good spectrum using T5 tubes as you can change the tubes to your liking. Many LEDs suffer from poor spectrum choice - this is not the fault of the technology itself but what aquarium light diodes manufacturers choose to use in constructing aquarium light units. 

T5 lights have proven results plus there are many choices for bulbs. Many experienced aquarists still use them to great outcomes. Tom Barr's planted aquarium below shows this well with striking coloration produced through the usage of multi-coloured T5 tubes.

Tom Barr T5 tank

Below is Mark Crow's planted tank under twin BML LEDs. Finding a good spectrum selection can take effort though. Examples such as these fully dispel the notion that "LEDs can't grow aquarium plants" or that "LEDs can't grow red aquarium plants well".

Mark Crow LED Dutch Style

At the end of the day, both can produce great planted tanks.

Head here to learn more about aquarium lighting for planted tanks

Head here to learn more about PAR values.

Head here to learn more about spectrum curves.

Also in Lighting

The best LED units for planted tanks in 2022
The best LED units for planted tanks in 2022

July 21, 2022 4 min read

While LEDs look fantastically sleek and are growing in popularity, the majority do not bring out the best coloration in plants. The ones featured here are what we consider the best available current options.
Read More
What factors give rise to stem elongation?
What factors give rise to stem elongation?

May 14, 2021 2 min read

Blue light suppresses inter-nodal stem distance in land plants, does this apply to aquatics?
Read More
Fine Tuning Light Spectrum
Fine Tuning Light Spectrum

September 04, 2020 1 min read

So, you have got the right light spectrum for your planted tanks. How can you boost plant colours further with your T5s or LEDs? Read on to find out more.
Read More

the 2hr newsletter